In a whirl of wind and noise, a helicopter lands at one of the area's level I trauma centers at the same time an ambulance pulls up outside the hospital. The two emergency vehicles contain patients suffering from similar traumatic injuries.

Outside, before rotors settle to a stop, the sounds can be deafening. Inside, crews communicate through an intercom system. If the patient was aware on the flight, the crew members may have had to speak loudly to let the patient know what's happening, explaining noises, vibrations and any distractions.

The ambulance ride may have had its own set of distractions for the crew and patient -- among them sirens and sharp turns.

Once patients arrive at a level I trauma center, they can equally benefit from the highest level of resources, training and experience to treat the most serious life threatening and disabling injuries. But a recent study found these patients' chances of the most positive outcomes may not be equal.

According to a recent study, the patient transported by air has both a 16 percent improved odds of survival and a better chance of being discharged to rehabilitation or intermediate facilities than the patient transported by ground, who, if he or she survives, is more likely to be discharged to a nursing home.

The study of 223,475 trauma patients older than 15, which was published in the April 18 Journal of the American Medical Association, said it wasn't clear what aspect of helicopter transport was responsible for the benefit.

But the medical directors of LifeFlight and STAT MedEvac, Pittsburgh-headquartered helicopter medical services, believe they know the reasons.

"It's not been proven by formal study, [but] my personal feelings and from 25 years of experience are that the first of two things is the level of care and training of the providers," said P.S. Martin, medical director of LifeFlight and director of the division of pre-hospital medicine for Allegheny General Hospital. He also is president of the Air Medical Physicians Association, an international group. "The second is shortened time of transport to care by the helicopter."

Francis X. Guyette, medical director for STAT MedEvac, which is run by the Center for Emergency Medicine of Western Pennsylvania and governed by UPMC, cites three reasons. First, he said, is a higher level of certification for helicopter medical crews, second is better equipment and third -- agreeing with Dr. Martin -- speed. "The aircraft fly at roughly 2 miles per minute in a straight line and are not subject to traffic or issues of topography," like bridges, tunnels or mountains.

"Typically an ambulance requires only a single paramedic," Dr. Guyette added. "A helicopter requires two providers, at least [one of them] a paramedic, and in every program in Pennsylvania, at least one of them is a nurse."

In the city of Pittsburgh, ambulance crews comprise two paramedics, but in most other local municipalities the makeup of ambulance crews is one paramedic and one emergency medical technician, who drives, Dr. Martin said.

STAT MedEvac crews comprise one paramedic who is flight paramedic certified and a nurse who is a certified flight registered nurse. LifeFlight crews are made up of nurses who must have five years of intensive care experience, and they must either be a paramedic or a pre-hospital registered nurse, which is a designation for someone state-trained to function as a paramedic.

AGH residents in emergency medicine do rotations on the helicopters, taking the place of one of the nurses, and Dr. Martin flies a shift every month or two. Residents and fellows in training also staff some STAT MedEvac aircraft.

The pilot is the third member of a helicopter crew.

Dr. Guyette said helicopters carry "several drugs that exceed the scope of practice of a standard paramedic and more sophisticated equipment, including monitors which are able to connect to intensive care devices." Those monitors include arterial lines that continuously measure blood pressure more accurately than an arm cuff, pulmonary artery catheters that measure heart function, and internal temperature monitors for hypothermia to protect the brain after cardiac arrest.

Other equipment and supplies aboard helicopters not usually found in ambulances include high-tech ventilators, transvenous pacemakers, chest tubes and a supply of type O blood, the universal donor, Dr. Martin said. If necessary, he said, crews also can surgically open the trachea and place an airway to help a patient breathe. "Ambulance crews typically aren't trained to do that."

Communication equipment aboard the aircraft includes radios and cell and satellite telephones. STAT MedEvac helicopters are in constant communication with an emergency physician. LifeFlight crews can be patched by radio or phone to an emergency doctor on hospital duty.

Helicopter evacuation began in the early 1950s during the Korean War and was expanded during the Vietnam War, according to a history of civilian helicopter ambulances in the December 1988 Annals of Surgery.

Some police agencies used helicopters for medical service in the late 1960s, Dr. Martin said, and the first hospital-based service started in Colorado in 1972, according to the Annals of Surgery.

LifeFlight was founded in 1978 as one of the first hospital-based services east of the Mississippi River. STAT MedEvac is about 25 years old.

In the beginning, helicopter medical services weren't nearly as sophisticated as they are today.

"[Providers are] more and more specialized," Dr. Guyette said. "The people who fly are professionals whose primary job is critical care transport as opposed to in the early days [when they were] just a regular paramedic or a nurse in the emergency department who was asked to go on the helicopter."

There is specialized training for airway management, insertion of breathing tubes, surgical airways and control of hemorrhaging. The crews train on computer-controlled, life-sized mannequins that can simulate virtually any emergency situation.

Equipment has gotten smaller over the years, allowing a wider variety of high-tech tools to be packed aboard the small aircraft.

Originally, the helicopters were single-engine but evolved to two-engine, which provided more lift and more space, Dr. Martin said.

Also part of the evolution was the addition of two vehicle safety features: night vision goggles and terrain awareness warning systems.

Helicopter transport is expensive, "probably five times more" than the cost of ground transport, Dr. Guyette said. "It varies a lot by distance and by whether a specialty team is involved, a heart-lung machine or a baby in an isolette. It's equivalent to about one day in [intensive care], which is important, because we can shorten a patient's stay in a hospital."

But helicopter transport will never replace ground transport -- for one thing, they cannot fly in bad weather -- and there are complicated guidelines established by the state of Pennsylvania for when aircraft should be used.

Dr. Martin said ambulances continue to be the first choice for patients who are stable, who do not need special medication or interventions that only air transport teams can provide. When time is not crucial for a diagnosis, the ambulance is the first choice as well, he said.

"Some examples include a stroke patient outside of the window for treatment using [clot-busting drug] tPA or other interventions, chest pain patients who are now pain free and not having an active heart attack, isolated burns that do not involve the airway or any complicating factors, any condition that can be easily stabilized by ground crews," Dr. Martin said.

He added if waiting for the helicopter takes longer than an ambulance to the chosen hospital, the ambulance may be best in even more serious cases, "unless an urgent intervention by the flight team is necessary."

First Published: July 9, 2012, 8:00 a.m.